Apparatus for the treatment of bundle of filaments

ABSTRACT

The specification describes an apparatus for the treatment of a bundle of filaments with a jet of fluid under pressure. A distribution chamber is formed with at least one conduit for feeding fluid under pressure thereto, an outlet duct connected to said distribution chamber by a smooth, inwardly convex surface, formed as a curve of revolution, coaxial with the outlet duct, and a convergent inlet member to the chamber connected to a tube, coaxial with the outlet duct, and extending into the distribution chamber, the free end of the tube being located within and spaced from said smooth surface at the junction thereof with said outlet duct.

UnitedStates Patent Inventors Jacques Fellous Boulogne Blllancourt; Pierre Goullioud, Ecully, France Appl. No. 826,997 Filed May 22, 1969 Patented Apr. 27, 1971 Assignee Societe Rhodiaoeta Paris, France Priority May 22, 1968 France 50048/68 APPARATUS FOR THE TREATMENT OF BUNDLE OF FILAMENTS [56] References Cited UNITED STATES PATENTS 3,452,910 7/ 1969 Richter 226/97X FOREIGN PATENTS 942,822 2/1949 France 226/97 Primary ExaminerAllen N. Knowles Attorney-Cushman, Darby and Cushman ABSTRACT: The specification describes an apparatus for the treatment of a bundle of filaments with a jet of fluid under pressure. A distribution chamber is formed with at least one conduit for feeding fluid under pressure thereto, an outlet duct connected to said distribution chamber by a smooth, inwardly convex surface, formed as a curve of revolution, coaxial with the outlet duct, and a convergent inlet member to the chamber connected to a tube, coaxial with the outlet duct, and extending into the distribution chamber, the free end of the tube being located within and spaced from said smooth surface at the junction thereof with said outlet duct.

APPARATUS FOR THE TREATMENT OF BUNDLE OF FILAMENTS The present invention relates to apparatus for the treatment, by means of a pressure fluid, of a bundle of continuous, moving chemical filaments.

it is well known in the textile industry to utilize fluid jet apparatus for the treatment of a bundle of filaments, notably for the manufacture of a nonwoven web or lap constituted by con tinuous filaments of orientated structure arranged at random and in nonparallel manner across the web or lap.

The preparation of such webs, sometimes known as spun bonded" in the US. literature, consists, schematically, in extruding a molten (or even dissolved) organic polymer through a spinneret, in orientating the extruded filaments by drawing the bundle with the aid of one or more fluid-jet apparatus, notably compressed air jet apparatus and, finally, in receiving the bundle in predetermined manner on a moving belt the velocity and direction of advance of which are adjusted in such manner as to form a web or lap which is substantially uniform and which has the desired thickness.

An advantageous apparatus for the performance of this technique comprises a generally frustoconical inlet orifice opening into a chamber provided with one or more fluid feed conduits and prolonged towards its downstream portion by a cylindrical tube. In a preferred embodiment which is frequently described in the literature, the widened or flared inlet orifice is connected with the chamber in such manner as to form an annular space which is inclined relatively to the direction of travel of the yarn or thread, in such manner as to aspirate and entrain the bundle of filaments. ln this device,

which gives excellent results, the fluid is throttled considerably as it enters the passage conduit of the bundle, in such manner that it necessitates a considerable quantity of air (thus involving high working costs) and it does not permit the achievement of velocity levels which are adequate to enable the successful achievement, by drawing, of molecular orientation of the polymer constituting the filaments of the bundle.

According to the invention there is provided apparatus for the treatment of a bundle of filaments with a jet of fluid under pressure, such apparatus comprising a distribution chamber having at least one conduit for feeding fluid under pressure thereto, an outlet duct connected to said distribution chamber by a smooth inwardly convex surface, formed as a curve of revolution, coaxial with the outlet duct, and a convergent inlet member to the chamber connected to a tube, coaxial with the outlet duct, and extending into the distribution chamber, the free end of the tube being located within and spaced from said smooth surface at the junction thereof with said outlet duct.

In one embodiment the outlet duct is provided with a coaxia] divergent extension at the downstream end thereof. This arrangement considerably facilitates the guiding of the bundle of filaments in the apparatus and by ensuring expansion of the fluid, improves the speeding-up of the bundle velocity. Advantageously the divergent extension is' provided with a coaxial outlet tube extension at the downstream end thereof, the diameter of the cylindrical extension corresponds to that of the downstream end of the divergent extension, whereas its length may vary within wide limits. In practice, the tube and the duct and the outlet tube are cylindrical and the divergent portion has the shape of a straight (or right) come frustum.

In a variant, the outlet tube may exhibit cylindrical section, flattening gradually in such manner as to distribute the filaments in line, thus assisting the uniform and homogeneous formation of the web.

As already stated, it is important that all the means involved in the passage of the bundle should be perfectly aligned, so that the bundle is extremely well focused and stable on the impact or takeup means situated downstream of the apparatus. Consequently, the filaments of the bundle are perfectly well distributed in the web.

Advantageously, the free end of said tube and said smooth surface adjacent thereto define an annular space having a first area, and said smooth surface encloses a second area at the location of said free end, and wherein said first area is between 0.1 and 0.6 of said second area, preferably between 0.25 and 0.40 of said second area.

The absence, in the apparatus of the invention, of any protuberances, inclined faces or other uneven or rough surfaces makes it possible to process the bundle of filaments under constant pressure and at a stabilized rate, thus avoiding the setting up of parasite turbulence which would result in the tangling of the filaments and thus prevent the separation thereof at the instant of formation of the web or lap.

The apparatus according to the invention may be manufactured from any suitable materials, such as brass, stainless steel, ceramic material or plastics material, and by any suitable techniques, such as machining or moulding.

The pressure of the fluid utilized may cover an extremely wide range, as a function of both the results which is desired to achieve and the respective dimensions of the essential parts constituting the apparatus. Generally, the fluid is a gas, which may be hot or cold, notably an inert gas, such as nitrogen or steam. For reasons of an economic nature, compressed air is used. ln practice, compressed air at ambient temperature is used under a pressure ranging between l and 6 bars, preferably 2.5 to 4 bars, measured in the distribution chamber.

The apparatus according to the invention may advantageously be utilized in the process previously described for the preparation of nonwoven webs or laps constituted by continuous filaments, wherein it serves jointly for the advancing and drawing of the bundle of filaments. I

As compared with prior devices known in this field of application, it has numerous advantages. In fact, the tube prolonging the inlet orifices, since its free end is situated at the level of the junction of the smooth surface and the outlet duct, involves practically speaking no throttling of the fluid. lt thus becomes possible to diminish the fluid consumption to a considerable degree, and to achieve fluid velocity levels, which are sufficient for obtaining the tensions necessary for the drawing of the bundle of filaments, without setting up disturbing turbulence effects on the bundle.

In order that the invention may more readily be understood the following description is given, merely by way of example, reference being made to the accompanying drawing, in which the sole H6. is a schematic cross section of one embodiment of apparatus according to the invention.

Referring now to the drawing, there is illustrated a funnelshaped inlet member 1 provided with a coaxial downwardly extending tube 2. The tube 2 extends into a distribution chamber 3 provided with a plurality of fluid inlets 4. Coaxial with the tube 2 and the funnel l is an outlet duct 5 having, at its lower downstream end, a divergent extension 6 of frustoconical form. Downstream of this extension 6 is a cylindrical outlet tube extension 7, the diameter of which corresponds to the wider diameter of the divergent extension 6.

As can be seen from the FlG., the distribution chamber 3 is provided with a smooth surface 8 which is inwardly convex, being formed as a curve of revolution about the common axis 9 of the inlet member 1, the tube 2, the outlet duct 5, and the extensions 6 and 7. The lower end 10 of the tube 2 is adjacent the junction between the smooth surface 8 and the inner surface of the outlet duct 5 and is spaced therefrom. Thus, an annular space is formed between the tube and the smooth surface, through which fluid from the chamber 3 passes into the outlet duct 5, and acts upon the bundle of filament passing in through the inlet member 1 and the tube 2 and so out through the duct 5 and extensions 6 and 7.

EXAMPLE Using the apparatus described above, through a spinneret pierced with 70 cylindrical apertures, 0.6 mm. in diameter, was extruded molten ethylene polyterephthalate (intrinsic viscosity after drawing, 0.68 determined at 25C. on a 0.5 percent solution in orthochlorophenol). The material extrusion rate was regulated at 5.2 grams per minute per aperture.

The bundle of filaments was assembled in a device according to the inventionthe features thereof are given hereinbelow-arranged at a distance of 150 cm. from the spinneret, in such manner that the filaments were cooled in ambient air as they travelled along the spinneret/apparatus path of travel.

With the aid of an oscillating deflector, the bundle of filaments having orientated structure was guided on to an endless moving belt on which was formed a nonwoven web or lap constituted by continuous filaments disposed at random and in nonparallel fashion, the web or lap weighing approximately 250 g/m In the web or lap, the elementary filaments had a unit count of 8.8 dtex (8 denier); they were not entangled but are clearly separated from each other.

The apparatus used had the following features:

Material c Stainless steel. Overall length 310 mm. Height of the inlet member (1)., 150 mm. Maximum diameter of the inlet member (1) 100 mm. Length of the cylindrical tube (2) 90 mm. Internal diameter of the cylindrical tube (2) 9 mm. External diameter of the cylindrical tube (2) 11 mm. Diameter of the cylindrical distribution chamber (3). 200 mm. Height of the distribution chamber (3)- 50 111111. Number of fluid-supplying conduits (4) 2.

Diameter of the cylindrical outlet duct (5) 13.3 mm. Length of the cylindrical outlet duct (5) 90 mm. Height of the divergent extension (6) mm. Diameter of the outlet of the divergent extension (6). mm. Annular space/outlet duct section ratio 0.31. Fluid utilised- Compressed air. Temperature of the fluid Ambient.

Pressure of the fluid in the distribution eharnbcr. 3.8 bars gauge.

We claim:

1. In an apparatus for the drawing and advance of a bundle of continuous chemical filament by means of a fluid under pressure, comprising a distribution chamber, at least one conduit for feeding fluid under pressure to said distribution chamber, an outlet duct to said distribution chamber, a smooth inwardly convex surface joining said duct to said distribution chamber and formed as a curve of revolution, a common axis to said outlet duct and smooth surface and a convergent inlet member to said distribution chamber, the improvement consisting in a tube coaxial with said common axis, connected to said inlet member and extending into said distribution chamber and a free downstream end to said tube located within and spaced from said smooth surface at the level of the junction point thereof with said outlet duct.

2. The improvement as defined in claim 1, wherein said free end of said tube and said smooth surface adjacent thereto define an annular space having a first area, and said smooth surface encloses a second area at the location of said free end, and wherein said first area is between 0.1 and 0.6 of said second area.

3. The improvement as defined in claim 1, wherein said free end to said tube and said smooth surface adjacent thereto define an annular space having a first area, and said smooth surface encloses a second area at the location of said free end, and wherein said first area is between 0.25 and 0.40 of said second area. 

1. In an apparatus for the drawing and advance of a bundle of continuous chemical filament by means of a fluid under pressure, comprising a distribution chamber, at least one conduit for feeding fluid under pressure to said distribution chamber, an outlet duct to said distribution chamber, a smooth inwardly convex surface joining said duct to said distribution chamber and formed as a curve of revolution, a common axis to said outlet duct and smooth surface and a convergent inlet member to said distribution chamber, the improvement consisting in a tube coaxial with said common axis, connected to said inlet member and extending into said distribution chamber and a free downstream end to said tube located within and spaced from said smooth surface at the level of the junction point thereof with said outlet duct.
 2. The improvement as defined in claim 1, wherein said free end of said tube and said smooth surface adjacent thereto define an annular space having a first area, and said smooth surface encloses a second area at the location of said free end, and wherein said first area is between 0.1 and 0.6 of said second area.
 3. The improvement as defined in claim 1, wherein said free end to said tube and said smooth surface adjacent thereto define an annular space having a first area, and said smooth surface encloses a second area at the location of said free end, and wherein said first area is between 0.25 and 0.40 of said second area. 